<?php
/**
 * PHPMailer RFC821 SMTP email transport class.
 * PHP Version 5
 * @package PHPMailer
 * @link https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
 * @author Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
 * @author Jim Jagielski (jimjag) <jimjag@gmail.com>
 * @author Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
 * @author Brent R. Matzelle (original founder)
 * @copyright 2014 Marcus Bointon
 * @copyright 2010 - 2012 Jim Jagielski
 * @copyright 2004 - 2009 Andy Prevost
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @note This program is distributed in the hope that it will be useful - WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 */

/**
 * PHPMailer RFC821 SMTP email transport class.
 * Implements RFC 821 SMTP commands and provides some utility methods for sending mail to an SMTP server.
 * @package PHPMailer
 * @author Chris Ryan
 * @author Marcus Bointon <phpmailer@synchromedia.co.uk>
 */
class SMTP
{
	/**
	 * The PHPMailer SMTP version number.
	 * @var string
	 */
	const VERSION = '5.2.16';

	/**
	 * SMTP line break constant.
	 * @var string
	 */
	const CRLF = "\r\n";

	/**
	 * The SMTP port to use if one is not specified.
	 * @var integer
	 */
	const DEFAULT_SMTP_PORT = 25;

	/**
	 * The maximum line length allowed by RFC 2822 section 2.1.1
	 * @var integer
	 */
	const MAX_LINE_LENGTH = 998;

	/**
	 * Debug level for no output
	 */
	const DEBUG_OFF = 0;

	/**
	 * Debug level to show client -> server messages
	 */
	const DEBUG_CLIENT = 1;

	/**
	 * Debug level to show client -> server and server -> client messages
	 */
	const DEBUG_SERVER = 2;

	/**
	 * Debug level to show connection status, client -> server and server -> client messages
	 */
	const DEBUG_CONNECTION = 3;

	/**
	 * Debug level to show all messages
	 */
	const DEBUG_LOWLEVEL = 4;

	/**
	 * The PHPMailer SMTP Version number.
	 * @var string
	 * @deprecated Use the `VERSION` constant instead
	 * @see SMTP::VERSION
	 */
	public $Version = '5.2.16';

	/**
	 * SMTP server port number.
	 * @var integer
	 * @deprecated This is only ever used as a default value, so use the `DEFAULT_SMTP_PORT` constant instead
	 * @see SMTP::DEFAULT_SMTP_PORT
	 */
	public $SMTP_PORT = 25;

	/**
	 * SMTP reply line ending.
	 * @var string
	 * @deprecated Use the `CRLF` constant instead
	 * @see SMTP::CRLF
	 */
	public $CRLF = "\r\n";

	/**
	 * Debug output level.
	 * Options:
	 * * self::DEBUG_OFF (`0`) No debug output, default
	 * * self::DEBUG_CLIENT (`1`) Client commands
	 * * self::DEBUG_SERVER (`2`) Client commands and server responses
	 * * self::DEBUG_CONNECTION (`3`) As DEBUG_SERVER plus connection status
	 * * self::DEBUG_LOWLEVEL (`4`) Low-level data output, all messages
	 * @var integer
	 */
	public $do_debug = self::DEBUG_OFF;

	/**
	 * How to handle debug output.
	 * Options:
	 * * `echo` Output plain-text as-is, appropriate for CLI
	 * * `html` Output escaped, line breaks converted to `<br>`, appropriate for browser output
	 * * `error_log` Output to error log as configured in php.ini
	 *
	 * Alternatively, you can provide a callable expecting two params: a message string and the debug level:
	 * <code>
	 * $smtp->Debugoutput = function($str, $level) {echo "debug level $level; message: $str";};
	 * </code>
	 * @var string|callable
	 */
	public $Debugoutput = 'echo';

	/**
	 * Whether to use VERP.
	 * @link http://en.wikipedia.org/wiki/Variable_envelope_return_path
	 * @link http://www.postfix.org/VERP_README.html Info on VERP
	 * @var boolean
	 */
	public $do_verp = false;

	/**
	 * The timeout value for connection, in seconds.
	 * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2
	 * This needs to be quite high to function correctly with hosts using greetdelay as an anti-spam measure.
	 * @link http://tools.ietf.org/html/rfc2821#section-4.5.3.2
	 * @var integer
	 */
	public $Timeout = 300;

	/**
	 * How long to wait for commands to complete, in seconds.
	 * Default of 5 minutes (300sec) is from RFC2821 section 4.5.3.2
	 * @var integer
	 */
	public $Timelimit = 300;

	/**
	 * The socket for the server connection.
	 * @var resource
	 */
	protected $smtp_conn;

	/**
	 * Error information, if any, for the last SMTP command.
	 * @var array
	 */
	protected $error = array(
		'error' => '',
		'detail' => '',
		'smtp_code' => '',
		'smtp_code_ex' => ''
	);

	/**
	 * The reply the server sent to us for HELO.
	 * If null, no HELO string has yet been received.
	 * @var string|null
	 */
	protected $helo_rply = null;

	/**
	 * The set of SMTP extensions sent in reply to EHLO command.
	 * Indexes of the array are extension names.
	 * Value at index 'HELO' or 'EHLO' (according to command that was sent)
	 * represents the server name. In case of HELO it is the only element of the array.
	 * Other values can be boolean TRUE or an array containing extension options.
	 * If null, no HELO/EHLO string has yet been received.
	 * @var array|null
	 */
	protected $server_caps = null;

	/**
	 * The most recent reply received from the server.
	 * @var string
	 */
	protected $last_reply = '';

	/**
	 * Output debugging info via a user-selected method.
	 * @see SMTP::$Debugoutput
	 * @see SMTP::$do_debug
	 * @param string $str Debug string to output
	 * @param integer $level The debug level of this message; see DEBUG_* constants
	 * @return void
	 */
	protected function edebug($str, $level = 0)
	{
		if ($level > $this->do_debug) {
			return;
		}
		//Avoid clash with built-in function names
		if (!in_array($this->Debugoutput, array('error_log', 'html', 'echo')) and is_callable($this->Debugoutput)) {
			call_user_func($this->Debugoutput, $str, $this->do_debug);
			return;
		}
		switch ($this->Debugoutput) {
			case 'error_log':
				//Don't output, just log
				error_log($str);
				break;
			case 'html':
				//Cleans up output a bit for a better looking, HTML-safe output
				echo htmlentities(
					preg_replace('/[\r\n]+/', '', $str),
					ENT_QUOTES,
					'UTF-8'
				)
				. "<br>\n";
				break;
			case 'echo':
			default:
				//Normalize line breaks
				$str = preg_replace('/(\r\n|\r|\n)/ms', "\n", $str);
				echo gmdate('Y-m-d H:i:s') . "\t" . str_replace(
					"\n",
					"\n                   \t                  ",
					trim($str)
				)."\n";
		}
	}

	/**
	 * Connect to an SMTP server.
	 * @param string $host SMTP server IP or host name
	 * @param integer $port The port number to connect to
	 * @param integer $timeout How long to wait for the connection to open
	 * @param array $options An array of options for stream_context_create()
	 * @access public
	 * @return boolean
	 */
	public function connect($host, $port = null, $timeout = 30, $options = array())
	{
		static $streamok;
		//This is enabled by default since 5.0.0 but some providers disable it
		//Check this once and cache the result
		if (is_null($streamok)) {
			$streamok = function_exists('stream_socket_client');
		}
		// Clear errors to avoid confusion
		$this->setError('');
		// Make sure we are __not__ connected
		if ($this->connected()) {
			// Already connected, generate error
			$this->setError('Already connected to a server');
			return false;
		}
		if (empty($port)) {
			$port = self::DEFAULT_SMTP_PORT;
		}
		// Connect to the SMTP server
		$this->edebug(
			"Connection: opening to $host:$port, timeout=$timeout, options=".var_export($options, true),
			self::DEBUG_CONNECTION
		);
		$errno = 0;
		$errstr = '';
		if ($streamok) {
			$socket_context = stream_context_create($options);
			//Suppress errors; connection failures are handled at a higher level
			$this->smtp_conn = @stream_socket_client(
				$host . ":" . $port,
				$errno,
				$errstr,
				$timeout,
				STREAM_CLIENT_CONNECT,
				$socket_context
			);
		} else {
			//Fall back to fsockopen which should work in more places, but is missing some features
			$this->edebug(
				"Connection: stream_socket_client not available, falling back to fsockopen",
				self::DEBUG_CONNECTION
			);
			$this->smtp_conn = fsockopen(
				$host,
				$port,
				$errno,
				$errstr,
				$timeout
			);
		}
		// Verify we connected properly
		if (!is_resource($this->smtp_conn)) {
			$this->setError(
				'Failed to connect to server',
				$errno,
				$errstr
			);
			$this->edebug(
				'SMTP ERROR: ' . $this->error['error']
				. ": $errstr ($errno)",
				self::DEBUG_CLIENT
			);
			return false;
		}
		$this->edebug('Connection: opened', self::DEBUG_CONNECTION);
		// SMTP server can take longer to respond, give longer timeout for first read
		// Windows does not have support for this timeout function
		if (substr(PHP_OS, 0, 3) != 'WIN') {
			$max = ini_get('max_execution_time');
			// Don't bother if unlimited
			if ($max != 0 && $timeout > $max) {
				@set_time_limit($timeout);
			}
			stream_set_timeout($this->smtp_conn, $timeout, 0);
		}
		// Get any announcement
		$announce = $this->get_lines();
		$this->edebug('SERVER -> CLIENT: ' . $announce, self::DEBUG_SERVER);
		return true;
	}

	/**
	 * Initiate a TLS (encrypted) session.
	 * @access public
	 * @return boolean
	 */
	public function startTLS()
	{
		if (!$this->sendCommand('STARTTLS', 'STARTTLS', 220)) {
			return false;
		}

		//Allow the best TLS version(s) we can
		$crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT;

		//PHP 5.6.7 dropped inclusion of TLS 1.1 and 1.2 in STREAM_CRYPTO_METHOD_TLS_CLIENT
		//so add them back in manually if we can
		if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')) {
			$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
			$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
		}

		// Begin encrypted connection
		if (!stream_socket_enable_crypto(
			$this->smtp_conn,
			true,
			$crypto_method
		)) {
			return false;
		}
		return true;
	}

	/**
	 * Perform SMTP authentication.
	 * Must be run after hello().
	 * @see hello()
	 * @param string $username The user name
	 * @param string $password The password
	 * @param string $authtype The auth type (PLAIN, LOGIN, NTLM, CRAM-MD5, XOAUTH2)
	 * @param string $realm The auth realm for NTLM
	 * @param string $workstation The auth workstation for NTLM
	 * @param null|OAuth $OAuth An optional OAuth instance (@see PHPMailerOAuth)
	 * @return bool True if successfully authenticated.* @access public
	 */
	public function authenticate(
		$username,
		$password,
		$authtype = null,
		$realm = '',
		$workstation = '',
		$OAuth = null
	) {
		if (!$this->server_caps) {
			$this->setError('Authentication is not allowed before HELO/EHLO');
			return false;
		}

		if (array_key_exists('EHLO', $this->server_caps)) {
		// SMTP extensions are available. Let's try to find a proper authentication method

			if (!array_key_exists('AUTH', $this->server_caps)) {
				$this->setError('Authentication is not allowed at this stage');
				// 'at this stage' means that auth may be allowed after the stage changes
				// e.g. after STARTTLS
				return false;
			}

			self::edebug('Auth method requested: ' . ($authtype ? $authtype : 'UNKNOWN'), self::DEBUG_LOWLEVEL);
			self::edebug(
				'Auth methods available on the server: ' . implode(',', $this->server_caps['AUTH']),
				self::DEBUG_LOWLEVEL
			);

			if (empty($authtype)) {
				foreach (array('CRAM-MD5', 'LOGIN', 'PLAIN', 'NTLM', 'XOAUTH2') as $method) {
					if (in_array($method, $this->server_caps['AUTH'])) {
						$authtype = $method;
						break;
					}
				}
				if (empty($authtype)) {
					$this->setError('No supported authentication methods found');
					return false;
				}
				self::edebug('Auth method selected: '.$authtype, self::DEBUG_LOWLEVEL);
			}

			if (!in_array($authtype, $this->server_caps['AUTH'])) {
				$this->setError("The requested authentication method \"$authtype\" is not supported by the server");
				return false;
			}
		} elseif (empty($authtype)) {
			$authtype = 'LOGIN';
		}
		switch ($authtype) {
			case 'PLAIN':
				// Start authentication
				if (!$this->sendCommand('AUTH', 'AUTH PLAIN', 334)) {
					return false;
				}
				// Send encoded username and password
				if (!$this->sendCommand(
					'User & Password',
					base64_encode("\0" . $username . "\0" . $password),
					235
				)
				) {
					return false;
				}
				break;
			case 'LOGIN':
				// Start authentication
				if (!$this->sendCommand('AUTH', 'AUTH LOGIN', 334)) {
					return false;
				}
				if (!$this->sendCommand("Username", base64_encode($username), 334)) {
					return false;
				}
				if (!$this->sendCommand("Password", base64_encode($password), 235)) {
					return false;
				}
				break;
			case 'XOAUTH2':
				//If the OAuth Instance is not set. Can be a case when PHPMailer is used
				//instead of PHPMailerOAuth
				if (is_null($OAuth)) {
					return false;
				}
				$oauth = $OAuth->getOauth64();

				// Start authentication
				if (!$this->sendCommand('AUTH', 'AUTH XOAUTH2 ' . $oauth, 235)) {
					return false;
				}
				break;
			case 'NTLM':
				/*
				 * ntlm_sasl_client.php
				 * Bundled with Permission
				 *
				 * How to telnet in windows:
				 * http://technet.microsoft.com/en-us/library/aa995718%28EXCHG.65%29.aspx
				 * PROTOCOL Docs http://curl.haxx.se/rfc/ntlm.html#ntlmSmtpAuthentication
				 */
				require_once 'extras/ntlm_sasl_client.php';
				$temp = new stdClass;
				$ntlm_client = new ntlm_sasl_client_class;
				//Check that functions are available
				if (!$ntlm_client->Initialize($temp)) {
					$this->setError($temp->error);
					$this->edebug(
						'You need to enable some modules in your php.ini file: '
						. $this->error['error'],
						self::DEBUG_CLIENT
					);
					return false;
				}
				//msg1
				$msg1 = $ntlm_client->TypeMsg1($realm, $workstation); //msg1

				if (!$this->sendCommand(
					'AUTH NTLM',
					'AUTH NTLM ' . base64_encode($msg1),
					334
				)
				) {
					return false;
				}
				//Though 0 based, there is a white space after the 3 digit number
				//msg2
				$challenge = substr($this->last_reply, 3);
				$challenge = base64_decode($challenge);
				$ntlm_res = $ntlm_client->NTLMResponse(
					substr($challenge, 24, 8),
					$password
				);
				//msg3
				$msg3 = $ntlm_client->TypeMsg3(
					$ntlm_res,
					$username,
					$realm,
					$workstation
				);
				// send encoded username
				return $this->sendCommand('Username', base64_encode($msg3), 235);
			case 'CRAM-MD5':
				// Start authentication
				if (!$this->sendCommand('AUTH CRAM-MD5', 'AUTH CRAM-MD5', 334)) {
					return false;
				}
				// Get the challenge
				$challenge = base64_decode(substr($this->last_reply, 4));

				// Build the response
				$response = $username . ' ' . $this->hmac($challenge, $password);

				// send encoded credentials
				return $this->sendCommand('Username', base64_encode($response), 235);
			default:
				$this->setError("Authentication method \"$authtype\" is not supported");
				return false;
		}
		return true;
	}

	/**
	 * Calculate an MD5 HMAC hash.
	 * Works like hash_hmac('md5', $data, $key)
	 * in case that function is not available
	 * @param string $data The data to hash
	 * @param string $key  The key to hash with
	 * @access protected
	 * @return string
	 */
	protected function hmac($data, $key)
	{
		if (function_exists('hash_hmac')) {
			return hash_hmac('md5', $data, $key);
		}

		// The following borrowed from
		// http://php.net/manual/en/function.mhash.php#27225

		// RFC 2104 HMAC implementation for php.
		// Creates an md5 HMAC.
		// Eliminates the need to install mhash to compute a HMAC
		// by Lance Rushing

		$bytelen = 64; // byte length for md5
		if (strlen($key) > $bytelen) {
			$key = pack('H*', md5($key));
		}
		$key = str_pad($key, $bytelen, chr(0x00));
		$ipad = str_pad('', $bytelen, chr(0x36));
		$opad = str_pad('', $bytelen, chr(0x5c));
		$k_ipad = $key ^ $ipad;
		$k_opad = $key ^ $opad;

		return md5($k_opad . pack('H*', md5($k_ipad . $data)));
	}

	/**
	 * Check connection state.
	 * @access public
	 * @return boolean True if connected.
	 */
	public function connected()
	{
		if (is_resource($this->smtp_conn)) {
			$sock_status = stream_get_meta_data($this->smtp_conn);
			if ($sock_status['eof']) {
				// The socket is valid but we are not connected
				$this->edebug(
					'SMTP NOTICE: EOF caught while checking if connected',
					self::DEBUG_CLIENT
				);
				$this->close();
				return false;
			}
			return true; // everything looks good
		}
		return false;
	}

	/**
	 * Close the socket and clean up the state of the class.
	 * Don't use this function without first trying to use QUIT.
	 * @see quit()
	 * @access public
	 * @return void
	 */
	public function close()
	{
		$this->setError('');
		$this->server_caps = null;
		$this->helo_rply = null;
		if (is_resource($this->smtp_conn)) {
			// close the connection and cleanup
			fclose($this->smtp_conn);
			$this->smtp_conn = null; //Makes for cleaner serialization
			$this->edebug('Connection: closed', self::DEBUG_CONNECTION);
		}
	}

	/**
	 * Send an SMTP DATA command.
	 * Issues a data command and sends the msg_data to the server,
	 * finializing the mail transaction. $msg_data is the message
	 * that is to be send with the headers. Each header needs to be
	 * on a single line followed by a <CRLF> with the message headers
	 * and the message body being separated by and additional <CRLF>.
	 * Implements rfc 821: DATA <CRLF>
	 * @param string $msg_data Message data to send
	 * @access public
	 * @return boolean
	 */
	public function data($msg_data)
	{
		//This will use the standard timelimit
		if (!$this->sendCommand('DATA', 'DATA', 354)) {
			return false;
		}

		/* The server is ready to accept data!
		 * According to rfc821 we should not send more than 1000 characters on a single line (including the CRLF)
		 * so we will break the data up into lines by \r and/or \n then if needed we will break each of those into
		 * smaller lines to fit within the limit.
		 * We will also look for lines that start with a '.' and prepend an additional '.'.
		 * NOTE: this does not count towards line-length limit.
		 */

		// Normalize line breaks before exploding
		$lines = explode("\n", str_replace(array("\r\n", "\r"), "\n", $msg_data));

		/* To distinguish between a complete RFC822 message and a plain message body, we check if the first field
		 * of the first line (':' separated) does not contain a space then it _should_ be a header and we will
		 * process all lines before a blank line as headers.
		 */

		$field = substr($lines[0], 0, strpos($lines[0], ':'));
		$in_headers = false;
		if (!empty($field) && strpos($field, ' ') === false) {
			$in_headers = true;
		}

		foreach ($lines as $line) {
			$lines_out = array();
			if ($in_headers and $line == '') {
				$in_headers = false;
			}
			//Break this line up into several smaller lines if it's too long
			//Micro-optimisation: isset($str[$len]) is faster than (strlen($str) > $len),
			while (isset($line[self::MAX_LINE_LENGTH])) {
				//Working backwards, try to find a space within the last MAX_LINE_LENGTH chars of the line to break on
				//so as to avoid breaking in the middle of a word
				$pos = strrpos(substr($line, 0, self::MAX_LINE_LENGTH), ' ');
				//Deliberately matches both false and 0
				if (!$pos) {
					//No nice break found, add a hard break
					$pos = self::MAX_LINE_LENGTH - 1;
					$lines_out[] = substr($line, 0, $pos);
					$line = substr($line, $pos);
				} else {
					//Break at the found point
					$lines_out[] = substr($line, 0, $pos);
					//Move along by the amount we dealt with
					$line = substr($line, $pos + 1);
				}
				//If processing headers add a LWSP-char to the front of new line RFC822 section 3.1.1
				if ($in_headers) {
					$line = "\t" . $line;
				}
			}
			$lines_out[] = $line;

			//Send the lines to the server
			foreach ($lines_out as $line_out) {
				//RFC2821 section 4.5.2
				if (!empty($line_out) and $line_out[0] == '.') {
					$line_out = '.' . $line_out;
				}
				$this->client_send($line_out . self::CRLF);
			}
		}

		//Message data has been sent, complete the command
		//Increase timelimit for end of DATA command
		$savetimelimit = $this->Timelimit;
		$this->Timelimit = $this->Timelimit * 2;
		$result = $this->sendCommand('DATA END', '.', 250);
		//Restore timelimit
		$this->Timelimit = $savetimelimit;
		return $result;
	}

	/**
	 * Send an SMTP HELO or EHLO command.
	 * Used to identify the sending server to the receiving server.
	 * This makes sure that client and server are in a known state.
	 * Implements RFC 821: HELO <SP> <domain> <CRLF>
	 * and RFC 2821 EHLO.
	 * @param string $host The host name or IP to connect to
	 * @access public
	 * @return boolean
	 */
	public function hello($host = '')
	{
		//Try extended hello first (RFC 2821)
		return (boolean)($this->sendHello('EHLO', $host) or $this->sendHello('HELO', $host));
	}

	/**
	 * Send an SMTP HELO or EHLO command.
	 * Low-level implementation used by hello()
	 * @see hello()
	 * @param string $hello The HELO string
	 * @param string $host The hostname to say we are
	 * @access protected
	 * @return boolean
	 */
	protected function sendHello($hello, $host)
	{
		$noerror = $this->sendCommand($hello, $hello . ' ' . $host, 250);
		$this->helo_rply = $this->last_reply;
		if ($noerror) {
			$this->parseHelloFields($hello);
		} else {
			$this->server_caps = null;
		}
		return $noerror;
	}

	/**
	 * Parse a reply to HELO/EHLO command to discover server extensions.
	 * In case of HELO, the only parameter that can be discovered is a server name.
	 * @access protected
	 * @param string $type - 'HELO' or 'EHLO'
	 */
	protected function parseHelloFields($type)
	{
		$this->server_caps = array();
		$lines = explode("\n", $this->helo_rply);

		foreach ($lines as $n => $s) {
			//First 4 chars contain response code followed by - or space
			$s = trim(substr($s, 4));
			if (empty($s)) {
				continue;
			}
			$fields = explode(' ', $s);
			if (!empty($fields)) {
				if (!$n) {
					$name = $type;
					$fields = $fields[0];
				} else {
					$name = array_shift($fields);
					switch ($name) {
						case 'SIZE':
							$fields = ($fields ? $fields[0] : 0);
							break;
						case 'AUTH':
							if (!is_array($fields)) {
								$fields = array();
							}
							break;
						default:
							$fields = true;
					}
				}
				$this->server_caps[$name] = $fields;
			}
		}
	}

	/**
	 * Send an SMTP MAIL command.
	 * Starts a mail transaction from the email address specified in
	 * $from. Returns true if successful or false otherwise. If True
	 * the mail transaction is started and then one or more recipient
	 * commands may be called followed by a data command.
	 * Implements rfc 821: MAIL <SP> FROM:<reverse-path> <CRLF>
	 * @param string $from Source address of this message
	 * @access public
	 * @return boolean
	 */
	public function mail($from)
	{
		$useVerp = ($this->do_verp ? ' XVERP' : '');
		return $this->sendCommand(
			'MAIL FROM',
			'MAIL FROM:<' . $from . '>' . $useVerp,
			250
		);
	}

	/**
	 * Send an SMTP QUIT command.
	 * Closes the socket if there is no error or the $close_on_error argument is true.
	 * Implements from rfc 821: QUIT <CRLF>
	 * @param boolean $close_on_error Should the connection close if an error occurs?
	 * @access public
	 * @return boolean
	 */
	public function quit($close_on_error = true)
	{
		$noerror = $this->sendCommand('QUIT', 'QUIT', 221);
		$err = $this->error; //Save any error
		if ($noerror or $close_on_error) {
			$this->close();
			$this->error = $err; //Restore any error from the quit command
		}
		return $noerror;
	}

	/**
	 * Send an SMTP RCPT command.
	 * Sets the TO argument to $toaddr.
	 * Returns true if the recipient was accepted false if it was rejected.
	 * Implements from rfc 821: RCPT <SP> TO:<forward-path> <CRLF>
	 * @param string $address The address the message is being sent to
	 * @access public
	 * @return boolean
	 */
	public function recipient($address)
	{
		return $this->sendCommand(
			'RCPT TO',
			'RCPT TO:<' . $address . '>',
			array(250, 251)
		);
	}

	/**
	 * Send an SMTP RSET command.
	 * Abort any transaction that is currently in progress.
	 * Implements rfc 821: RSET <CRLF>
	 * @access public
	 * @return boolean True on success.
	 */
	public function reset()
	{
		return $this->sendCommand('RSET', 'RSET', 250);
	}

	/**
	 * Send a command to an SMTP server and check its return code.
	 * @param string $command The command name - not sent to the server
	 * @param string $commandstring The actual command to send
	 * @param integer|array $expect One or more expected integer success codes
	 * @access protected
	 * @return boolean True on success.
	 */
	protected function sendCommand($command, $commandstring, $expect)
	{
		if (!$this->connected()) {
			$this->setError("Called $command without being connected");
			return false;
		}
		//Reject line breaks in all commands
		if (strpos($commandstring, "\n") !== false or strpos($commandstring, "\r") !== false) {
			$this->setError("Command '$command' contained line breaks");
			return false;
		}
		$this->client_send($commandstring . self::CRLF);

		$this->last_reply = $this->get_lines();
		// Fetch SMTP code and possible error code explanation
		$matches = array();
		if (preg_match("/^([0-9]{3})[ -](?:([0-9]\\.[0-9]\\.[0-9]) )?/", $this->last_reply, $matches)) {
			$code = $matches[1];
			$code_ex = (count($matches) > 2 ? $matches[2] : null);
			// Cut off error code from each response line
			$detail = preg_replace(
				"/{$code}[ -]".($code_ex ? str_replace('.', '\\.', $code_ex).' ' : '')."/m",
				'',
				$this->last_reply
			);
		} else {
			// Fall back to simple parsing if regex fails
			$code = substr($this->last_reply, 0, 3);
			$code_ex = null;
			$detail = substr($this->last_reply, 4);
		}

		$this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);

		if (!in_array($code, (array)$expect)) {
			$this->setError(
				"$command command failed",
				$detail,
				$code,
				$code_ex
			);
			$this->edebug(
				'SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply,
				self::DEBUG_CLIENT
			);
			return false;
		}

		$this->setError('');
		return true;
	}

	/**
	 * Send an SMTP SAML command.
	 * Starts a mail transaction from the email address specified in $from.
	 * Returns true if successful or false otherwise. If True
	 * the mail transaction is started and then one or more recipient
	 * commands may be called followed by a data command. This command
	 * will send the message to the users terminal if they are logged
	 * in and send them an email.
	 * Implements rfc 821: SAML <SP> FROM:<reverse-path> <CRLF>
	 * @param string $from The address the message is from
	 * @access public
	 * @return boolean
	 */
	public function sendAndMail($from)
	{
		return $this->sendCommand('SAML', "SAML FROM:$from", 250);
	}

	/**
	 * Send an SMTP VRFY command.
	 * @param string $name The name to verify
	 * @access public
	 * @return boolean
	 */
	public function verify($name)
	{
		return $this->sendCommand('VRFY', "VRFY $name", array(250, 251));
	}

	/**
	 * Send an SMTP NOOP command.
	 * Used to keep keep-alives alive, doesn't actually do anything
	 * @access public
	 * @return boolean
	 */
	public function noop()
	{
		return $this->sendCommand('NOOP', 'NOOP', 250);
	}

	/**
	 * Send an SMTP TURN command.
	 * This is an optional command for SMTP that this class does not support.
	 * This method is here to make the RFC821 Definition complete for this class
	 * and _may_ be implemented in future
	 * Implements from rfc 821: TURN <CRLF>
	 * @access public
	 * @return boolean
	 */
	public function turn()
	{
		$this->setError('The SMTP TURN command is not implemented');
		$this->edebug('SMTP NOTICE: ' . $this->error['error'], self::DEBUG_CLIENT);
		return false;
	}

	/**
	 * Send raw data to the server.
	 * @param string $data The data to send
	 * @access public
	 * @return integer|boolean The number of bytes sent to the server or false on error
	 */
	public function client_send($data)
	{
		$this->edebug("CLIENT -> SERVER: $data", self::DEBUG_CLIENT);
		return fwrite($this->smtp_conn, $data);
	}

	/**
	 * Get the latest error.
	 * @access public
	 * @return array
	 */
	public function getError()
	{
		return $this->error;
	}

	/**
	 * Get SMTP extensions available on the server
	 * @access public
	 * @return array|null
	 */
	public function getServerExtList()
	{
		return $this->server_caps;
	}

	/**
	 * A multipurpose method
	 * The method works in three ways, dependent on argument value and current state
	 *   1. HELO/EHLO was not sent - returns null and set up $this->error
	 *   2. HELO was sent
	 *     $name = 'HELO': returns server name
	 *     $name = 'EHLO': returns boolean false
	 *     $name = any string: returns null and set up $this->error
	 *   3. EHLO was sent
	 *     $name = 'HELO'|'EHLO': returns server name
	 *     $name = any string: if extension $name exists, returns boolean True
	 *       or its options. Otherwise returns boolean False
	 * In other words, one can use this method to detect 3 conditions:
	 *  - null returned: handshake was not or we don't know about ext (refer to $this->error)
	 *  - false returned: the requested feature exactly not exists
	 *  - positive value returned: the requested feature exists
	 * @param string $name Name of SMTP extension or 'HELO'|'EHLO'
	 * @return mixed
	 */
	public function getServerExt($name)
	{
		if (!$this->server_caps) {
			$this->setError('No HELO/EHLO was sent');
			return null;
		}

		// the tight logic knot ;)
		if (!array_key_exists($name, $this->server_caps)) {
			if ($name == 'HELO') {
				return $this->server_caps['EHLO'];
			}
			if ($name == 'EHLO' || array_key_exists('EHLO', $this->server_caps)) {
				return false;
			}
			$this->setError('HELO handshake was used. Client knows nothing about server extensions');
			return null;
		}

		return $this->server_caps[$name];
	}

	/**
	 * Get the last reply from the server.
	 * @access public
	 * @return string
	 */
	public function getLastReply()
	{
		return $this->last_reply;
	}

	/**
	 * Read the SMTP server's response.
	 * Either before eof or socket timeout occurs on the operation.
	 * With SMTP we can tell if we have more lines to read if the
	 * 4th character is '-' symbol. If it is a space then we don't
	 * need to read anything else.
	 * @access protected
	 * @return string
	 */
	protected function get_lines()
	{
		// If the connection is bad, give up straight away
		if (!is_resource($this->smtp_conn)) {
			return '';
		}
		$data = '';
		$endtime = 0;
		stream_set_timeout($this->smtp_conn, $this->Timeout);
		if ($this->Timelimit > 0) {
			$endtime = time() + $this->Timelimit;
		}
		while (is_resource($this->smtp_conn) && !feof($this->smtp_conn)) {
			$str = @fgets($this->smtp_conn, 515);
			$this->edebug("SMTP -> get_lines(): \$data is \"$data\"", self::DEBUG_LOWLEVEL);
			$this->edebug("SMTP -> get_lines(): \$str is  \"$str\"", self::DEBUG_LOWLEVEL);
			$data .= $str;
			// If 4th character is a space, we are done reading, break the loop, micro-optimisation over strlen
			if ((isset($str[3]) and $str[3] == ' ')) {
				break;
			}
			// Timed-out? Log and break
			$info = stream_get_meta_data($this->smtp_conn);
			if ($info['timed_out']) {
				$this->edebug(
					'SMTP -> get_lines(): timed-out (' . $this->Timeout . ' sec)',
					self::DEBUG_LOWLEVEL
				);
				break;
			}
			// Now check if reads took too long
			if ($endtime and time() > $endtime) {
				$this->edebug(
					'SMTP -> get_lines(): timelimit reached ('.
					$this->Timelimit . ' sec)',
					self::DEBUG_LOWLEVEL
				);
				break;
			}
		}
		return $data;
	}

	/**
	 * Enable or disable VERP address generation.
	 * @param boolean $enabled
	 */
	public function setVerp($enabled = false)
	{
		$this->do_verp = $enabled;
	}

	/**
	 * Get VERP address generation mode.
	 * @return boolean
	 */
	public function getVerp()
	{
		return $this->do_verp;
	}

	/**
	 * Set error messages and codes.
	 * @param string $message The error message
	 * @param string $detail Further detail on the error
	 * @param string $smtp_code An associated SMTP error code
	 * @param string $smtp_code_ex Extended SMTP code
	 */
	protected function setError($message, $detail = '', $smtp_code = '', $smtp_code_ex = '')
	{
		$this->error = array(
			'error' => $message,
			'detail' => $detail,
			'smtp_code' => $smtp_code,
			'smtp_code_ex' => $smtp_code_ex
		);
	}

	/**
	 * Set debug output method.
	 * @param string|callable $method The name of the mechanism to use for debugging output, or a callable to handle it.
	 */
	public function setDebugOutput($method = 'echo')
	{
		$this->Debugoutput = $method;
	}

	/**
	 * Get debug output method.
	 * @return string
	 */
	public function getDebugOutput()
	{
		return $this->Debugoutput;
	}

	/**
	 * Set debug output level.
	 * @param integer $level
	 */
	public function setDebugLevel($level = 0)
	{
		$this->do_debug = $level;
	}

	/**
	 * Get debug output level.
	 * @return integer
	 */
	public function getDebugLevel()
	{
		return $this->do_debug;
	}

	/**
	 * Set SMTP timeout.
	 * @param integer $timeout
	 */
	public function setTimeout($timeout = 0)
	{
		$this->Timeout = $timeout;
	}

	/**
	 * Get SMTP timeout.
	 * @return integer
	 */
	public function getTimeout()
	{
		return $this->Timeout;
	}
}
